This invention relates to a thin film electroluminescence device generating electroluminescence upon application of an electric field.
This thin film electroluminescence device emits light of intense brightness and its light-emitting layer has low granularity. Consequently, it is anticipated that this electroluminescence device will be particularly advantageous when applied to a data communication terminal in the form of an image display device, replacing the conventional cathode ray tube.
The thin film electroluminescence device developed to date is the type whose light-emitting layer is prepared from ZnS mixed with Mn, Cu, or the like, to produce a monochromatic light such as a green or yellow light. However, no thin film electroluminescence device has been obtained which can emit white light.
In recent years, an electroluminescence device capable of emitting white light of high brightness has been proposed, whose light-emitting layer is prepared from ZnS:PrF.sub.3. The white light obtained by this device, however, has resulted from a combination of complementary colors. Therefore, said device fails to attain the color display function characterizing a white light-emitting electroluminescence device.
Another known thin film electroluminescence device is of the type whose light-emitting layer consists of a thin film of hydrogenated amorphous silicon carbide obtained by the glow-discharge decomposition of a gas consisting mainly of tetramethylsilane (TMS). Recently, attention has been focused on this electroluminescence device, whose emission spectrum covers the whole range of a visible light spectrum, and which can emit white light allowing for color display. At present, however, the brightness of the white light derived from said electroluminescence device is too low for practical purposes.